ata6616 ATMEL Corporation, ata6616 Datasheet - Page 96

• Manufacturer Part Number: ata6616
• Description: Microcontroller With Lin Transceiver, 5v Regulator And Watchdog
• Manufacturer: ATMEL Corporation

4.10.2.6
4.10.2.7
4.10.3
96
ATA6616/ATA6617 [Preliminary]
Alternate Port Functions
Digital Input Enable and Sleep Modes
Unconnected Pins
As shown in
Schmitt Trigger. The signal denoted SLEEP in the figure, is set by the MCU Sleep Controller in
Power-down or Power-save mode to avoid high power consumption if some input signals are left
floating, or have an analog signal level close to Vcc/2.
SLEEP is overridden for port pins enabled as external interrupt pins. If the external interrupt
request is not enabled, SLEEP is active also for these pins. SLEEP is also overridden by various
other alternate functions as described in
If a logic high level (“one”) is present on an asynchronous external interrupt pin configured as
“Interrupt on Rising Edge, Falling Edge, or Any Logic Change on Pin” while the external interrupt
is not enabled, the corresponding External Interrupt Flag will be set when resuming from the
above mentioned Sleep mode, as the clamping in these sleep mode produces the requested
logic change.
If some pins are unused, it is recommended to ensure that these pins have a defined level. Even
though most of the digital inputs are disabled in the deep sleep modes as described above, float-
ing inputs should be avoided to reduce current consumption in all other modes where the digital
inputs are enabled (Reset, Active mode and Idle mode).
The simplest method to ensure a defined level of an unused pin, is to enable the internal pull-up.
In this case, the pull-up will be disabled during reset. If low power consumption during reset is
important, it is recommended to use an external pull-up or pull-down. Connecting unused pins
directly to Vcc or GND is not recommended, since this may cause excessive currents if the pin is
accidentally configured as an output.
Most port pins have alternate functions in addition to being general digital I/Os.
shows how the port pin control signals from the simplified
alternate functions. The overriding signals may not be present in all port pins, but the figure
serves as a generic description applicable to all port pins in the AVR microcontroller family.
Figure
4-25, the digital input signal can be clamped to ground at the input of the
“Alternate Port Functions” on page
DRAFT
Figure 4-25
can be overridden by
96.
9132A–AUTO–10/08
Figure 4-29